An image capturing apparatus such as a video camera and a digital still camera is used for capturing a color image. A solid state image capturing element (composed of plurality of photoelectric conversion elements) such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) image sensors used in these cameras has sensitivity to from near-infrared wavelength bandwidth to near-ultraviolet wavelength bandwidth.
However, when the color image is captured, light signals in wavelength bandwidths that are invisible by a human eye (about 400 to 700 nm is visible) are noise components for a correct color image. Then, in order to provide the correct color image, by disposing infrared cut filters at photoelectric conversion elements of the solid state image capturing element, signals where light in the near-infrared wavelength bandwidth is removed should be detected.
In general, the infrared cut filters are disposed between an image capturing optical system and the solid state image element, an absorption type infrared cut filter composed of an infrared bandwidth absorption material and a reflective infrared cut filter utilizing a multilayer film interference.
In recent years, the image capturing apparatus is downsized. In general, the infrared cut filter has a thickness of about 1 to 3 mm. To thin the digital camera, the thickness of the infrared cut filter becomes a problem. In particular, in a camera module mounted to a mobile phone or a mobile terminal, it is essential to thin the image capturing optical system. In addition, the infrared cut filter should be mounted on the image capturing apparatus together with the solid state image capturing element. In terms of a production cost of the image capturing apparatus, an improvement is desirable.
Patent Document 1 discloses a solid state image capturing element where a flattened layer and on-chip lenses having an infrared absorption ability are laminated on photoelectric conversion elements. By providing the flattened layer and the on-chip lenses with the infrared absorption ability, the image capturing optical system can be thinned without disposing the infrared cut filters separately from the solid state image capturing element.
Patent Document 2 discloses a solid state image capturing element where an infrared absorption material is added to color filters disposed on photoelectric conversion elements, thereby removing infrared components by the color filters. Also, the image capturing optical system can be thinned without disposing the infrared cut filters separately from the solid state image capturing element.
Patent Document 1: Japanese Patent Application Laid-open No. 2004-200360
Patent Document 2: Japanese Patent Application Laid-open No. 2007-141876